Zusammenfassung This paper presents the results of studies on the amylase activity of various human biological fluids and tissue homogenates. 1. 1. The various amylase enzymes are characterised by different electrophoretic mobilities. Amylase from parotic gland differs from pancreatic amylase, bacterial amylase from animal amylase, as well as from human amylase. In human body and in human biological fluids respectively, including serum and urine, there are generally two fractions with amylase activity, one of which has a slower electrophoretic mobility, and corresponds to amylase from pancreas. In serum and urine of patients with pancreatitis, pancreas amylase predominates. 2. 2. Amylase activity is found in the area of proteins with slow electrophoretic mobility, that is between β- and γ-globulins. Slight starch disintegrating and glycolytic activities are also seen in the area of α-globulins. 3. 3. An exact coordination of amylase activity to one of the well known serum protein fractions is not possible. The enzymatic activities are found between such serum protein components. 4. 4. There are differences in the degree of amylase activity among the various analysed substrates. Parotic saliva and the homogenate of pancreatic gland, as well as duodenal and biliary fluids show extremely high amylase activity; on the contrary, serum and urine of healthy men and most of the human tissue extracts have a low enzyme activity. 5. 5. In certain tissue extracts, e.g ., in the homogenates of gastric and colonic mucous membrane, three different amylase-active components could be found. It is concluded that in the human body there exist two isoenzymes of amylase which differ by their respective electrophoretic mobilities: one of them, migrating with β 2 -globulins, is probably produced by the parotic gland, the other, moving with γ 1 -globulins, by the pancreatic gland. Amylase from pancreas is the fastest migrating enzyme.